General relativistic study of astrophysical jets with internal shocks

Abstract

We explore the possibility of formation of steady internal shocks in jets around black holes. We consider a fluid described by a relativistic equation of state, flowing about the axis of symmetry (θ = 0) in a Schwarzschild metric. We use two models for the jet geometry, (i) a conical geometry and (ii) a geometry with non-conical cross-section. Jet with conical geometry is smooth flow.While the jet with non-conical cross section undergoes multiple sonic point and even standing shock. The jet shock becomes stronger, as the shock location is situated further from the central black hole. Jets with very high energy and very low energy do not harbour shocks, but jets with intermediate energies do harbour shocks. One advantage of these shocks, as opposed to shocks mediated by external medium is that, these shocks have no effect on the jet terminal speed, but may act as possible sites for particle acceleration. Typically, a jet with energy 1.8 c 2 , will achieve a terminal speed of v ∞ = 0.813c for jet with any geometry. But for a jet of non-conical cross-section for which the length scale of the inner torus of the accretion disc is 40r g , then in addition, a steady shock will form at r sh ∼ 7.5r g and compression ratio of R ∼ 2.7. Moreover, electron-proton jet seems to harbour the strongest shock. We discuss possible consequences of such a scenario.

Jet launching radius in low-power radio-loud AGNs in advection-dominated accretion flows

“…Independently, we notice that Chakrabarti (1999), Chattopadhyay & Kumar (2016), Kumar & Chattopadhyay (2017), and Vyas & Chattopadhyay (2017) have also invoked a jet launching point in the vicinity of a shock. From our own study of particle acceleration, the acceleration is strongest at the shock location, and therefore, should produce the strongest outflows at that point.…”

Spectral and accretion evolution of H1743−322 during outbursts in RXTE era

“…We propose that the additional powerlaw component originated from the jet. The presence of shock close to base of the jet (Vyas & Chattopadhyay 2017) may produce non-thermal electrons. We checked if the same can be produced due to synchrotron emission from non-thermal electrons at the base of the jet.…”

Relativistic Jets From Black Hole Accretion Disc

“…If we consider a purely ideal flow, then at the base of the jet the three-velocity should be zero. The Bernoulli parameter which in Schwarzschild metric is E = hγ(1 − 2/r) [20], where h is the specific enthalpy, γ the total Lorentz factor and r the radial coordinate. At the jet base, it becomes E = h b (1 − 2/r b ), as γ b ≈ 1.…”

“…Here τ is a function of of the jet composition and is defined as τ = 2 − ξ + ξ /η. The methodology to solve equations (2.2-2.5) has been laid down in a series of papers [19,20,18,21]. Assuming the Thomson scattering cross-section i. e., when χ c = 1, we showed that relativistic terminal speeds could be achieved but the temperature of the jet at the base was found to be very high [19,18].…”